1. Field of the Invention
The present invention relates to voltage monitoring circuits and more particularly to a low voltage protection circuit for use with an associated circuit, such as a magnetic tape unit. The low voltage protection circuit prevents generation of erroneous control signals during fluctuations in an associated power supply. An application of such circuit could be to prevent a magnetic tape unit from generating erroneous magnetic tape control and power signals.
2. Description of the Prior Art
Power supplies can cause logic circuitry to produce erratic signals during power supply fluctuations caused by power-up, power-down or power failure conditions. These erratic signals can result in catastrophic equipment failure conditions since erroneous control signals can cause abnormal operations. If these erratic signals are applied to a magnetic tape unit, for example, it can be caused to completely unwind the magnetic tape from its spool and thereby prevent further automatic use of that tape.
Typically 5 volt power supplies are used for logic circuitry and .+-.18 volt power supplies are used for magnetic tape motor circuitry. Usually these two power supplies rise and decay at rates that do not cause erratic tape control signals. However, due to component tolerances or frequency of power fluctuations, erroneous tape control signals can result and thereby cause erroneous tape motion.
Accordingly, it is the object of the present invention to provide a low voltage protection circuit which can inhibit control and power signals in response to detection of low voltage conditions and which is itself not subject to erroneous operation due to such low voltage conditions.